Bis(2-ethylhexyl) phthalate inhibition on aerobic flocculent and granular sludge in the treatment of landfill leachate: a comparative study

The present study aimed to investigate bis(2-ethylhexyl) phthalate (DEHP) inhibition in the flocculent and granular sludge sequencing batch reactors (GSBRs) used for the treatment of landfill leachate. Three columns of laboratory-scale sequencing batch reactors were utilized to evaluate the inhibition of the suspended flocs and aerobic granular sludge. The inhibitory concentrations of DEHP were detected as the purpose of the specific oxygen uptake rate, soluble chemical oxygen demand (SCOD), and DEHP removal function. In addition, glucose was used as the main biogenic substrate to dilute landfill leachate at 20% ratios. The GSBRs reveald a high performance in the SCOD and DEHP removal at the concentrations of up to 200 µg/L though the process ceased at 200 and 400 µg of DEHP/L in the suspended flocs sequencing batch reactors (FSBRs). At different dosing concentrations of DEHP in the reactor, short and suitable time led to the gradual accumulation of inhibitory compounds. At the inhibitory concentrations, only limited degradation of DEHP occurred. Although the assimilatory removal of DEHP was low at the normal efficiency of the FSBR, it reached significant values in the GSBRs.